1. Field of the Invention
The present invention relates to a process for the preparation of a coil for an electric appliance useful in electric appliances such as rotating apparatuses (e.g., a motor or generator) or transformers and a coil for electric appliance.
2. Description of the Related Art
For example, there has been known an edgewise wound square coil as a coil for motor, the square coil being obtained by squarely winding an electric conductor having a rectangular cross section such that small sides of the cross section corresponds with the direction of the coil axis of the coil to helically superpose the wound conductor in the direction of the coil axis.
Such the edgewise wound square coil permits a proportion occupied by coil in a slot to enhance. Hence in the edgewise wound square coil, it is possible to increase the operation efficiency of a motor and also reduce the size and weight of the motor.
The edgewise wound square coil has been prepared, for example, as shown in FIG. 12 so far. In more detail, a pillar copper is cut to form strip-shaped coil fragments 51A to 51D for constituting a one-turn square coil, the edges of the coil fragments 51A to 51D are butted (i.e., brought into contact with) each other in order at three points and welded respectively in bonding portions 52 to form a one-turn square coil 51 in the form of circle (rectangle), and a terminal end 53 of the one-turn square coil 51 is brazed to a beginning end of another (next) one-turn square coil 51 prepared similarly, whereby a square coil having desired number of turns can be prepared. For example, the process is described in JP-A-2001-178052.
According to the above-mentioned process, the pillar copper is cut to form strip-shaped coil fragments 51A to 51D, and therefore it is expected that the coil fragments 51A to 51D is improved in processing properties and processing precision and further enhanced in material yield of the pillar copper resulting in good productivity and low-cost.